2)what is direct test??
Ans: In this method of testing, the de machine is loaded directly by means of mechanical brake coupled to the shaft of the machine.

The efficiency of the machine is cnlculated directly by measuring the power input and output.

The entire power output is wasted at the mechanical brake. Due to non-availability of large capacity loads for testing large machines in the laboratories, this method is used only for testing small de machines.

3)break test is example of which test??
Ans:direct test

4)Swinburn's test is simplest which type of test??
Ans: Indirect

5)what is indirect test??
Ans:In this method of testing, the losses are determined without actual loading of the machine.

If the total losses in the machine are known, the efficiency can be calculated.6)give one example of regenerative test of dc machine??
Ans: hopkinson's test